At present, there are two types of optical fiber connector systems in wide use; one is a low cost simple system that is referred to herein as the plex system, and the other is the military system. In the plex system, a plex housing is provided which has through bores with opposite ends. Each end receives an optic fiber plex connector, so the tips of fibers of the two connectors touch one another to transmit light between optic fiber cables that trail from the plex connectors. Each plex connector includes a plex frame with a through passage, and a terminus lying in the through passage, the optic fiber cable having a fiber that extends through the terminus. Each plex connector also includes a latch that holds it in a bore of a plex housing until the latch is released to withdraw the plex connector. This type of optic fiber connector system is of low cost and highly versatile. However, when used in a hostile environment, such as in a factory where solvent vapors or dust may reach the plex housing, or a drop of a corrosive chemical may be splattered onto the plex housing, the plex system is not satisfactory.
In a military-type optic fiber connector, two separate connectors are provided, each with a housing having multiple passages that each receives a terminus without a frame around it, with each terminus being removable only with a special tool. Often, one of the connectors holds alignment sleeves that align the termini. Metal shells surround each housing and an optic fiber cable extends from each terminus. When the two connectors are mated, the tips of multiple pairs of optical fibers abut one another. Also, the two mating shells are sealed to each other. The shells are also each sealed to each other around the corresponding housing and to the cables to provide physical protection and to keep out vapors and other possibly harmful material. While such military-style connectors provide reliable connections, they are expensive.
If an optical fiber connector system were available which provided much of the low cost and simple connections of a plex system, while providing at least some of the sealing and mechanical protection of a military system, such a system would find use in many somewhat hostile environments.
In accordance with one embodiment of the present invention, an optical fiber connector system is provided, which has many of the advantages of a plex system in providing low cost, versatile and simple optic fiber connections, and which also has some of the advantages of a military-style optic fiber connection system in providing sealing and physical protection. The system includes a plex housing with one or more bores having opposite ends that each receive a plex connector and forming an alignment bore portion that aligns ferrules of two mating plex connectors. The system also includes an assembly of shells, including a cylindrical middle shell that lies around the plex housing and that has an internal flange with a rectangular opening that closely receives the plex housing, the middle shell being fixed to the plex housing. The middle shell has front and rear ends that are each threaded, and that engage threaded ends of backshells that receive trailing optical fiber cables extending from the plex connectors. The shells are sealed to one another, and grommets at the ends of the backshells are sealed to the optic cables. The shells provide physical protection of the plex housing and plex connectors therein, and provide sealing against the entrance of vapor and the like into the region where the tips of optical fibers abut one another.